The present invention relates to a semiconductor device and a method for fabricating the same, more specifically, a semiconductor device including cobalt silicide film and a method for fabricating the same.
As a technique of decreasing the resistance of gate electrodes and source/drain diffused layers is known the so-called salicide (Self-Aligned Silicide) process of forming metal silicide films on their surfaces by self-alignment. In the salicide process, metal materials to be reacted with silicon are cobalt (Co), titanium (Ti), etc. are used (refer to, e.g., Japanese published unexamined patent application No. Hei 10-242081 (1998), Japanese published unexamined patent application No. 2003-68670, and Japanese published unexamined patent application No. 2001-156287).
In semiconductor devices whose structures are increasingly micronized, when a micronized gate electrode is silicided by using a Co film, the scatter of the resistance of the gate electrode is often abruptly increased. This phenomena is conspicuous in a gate electrode of a below 50 nm-gate length including 50 nm-gate length.